The present invention relates to a tristimulus value type photoelectric colorimeter with spectral sensitivity correcting function.
Conventionally, the photoelectric colorimeter (of tristimulus value type) is given a spectral sensitivity close to an isochromatic function [x(.gamma.), y(.gamma.), z(.gamma.)] by use of an optical filter and an optical sensor in combination.
The spectral sensitivity of this type of photoelectric colorimeter, however, is not entirely identical with the isochromatic function. Consequently, measured values have errors. And also, scattering of the spectral sensitivity among devices such as each optical filter, etc. causes the measured values to have instrumental errors. Therefore, in the case that accuracy of the absolute value as well as a measurement with few instrumental errors is required, a spectral type colorimeter is generally utilized that can bring the spectral sensitivity into a theoretically perfect identity with the isochromatic function. But disadvantageously, this conventional spectral type colorimeter is large-sized and expensive.